This invention relates to a metallic component such as an aircraft engine turbine blade that is formed with a high modulus orientation of a metal being aligned in the radial, i.e. primary, direction of the turbine blade.
Machines that utilize high speed components, such as an aircraft engine, produce high frequency vibrations. The high frequency vibrations are typically on the order of kilohertz and impose a variety of fluctuating high cycle fatigue stresses on the high speed components of the machine. Often, the limiting factor in the life of a high speed component is high cycle fatigue stress. While the present invention is described in the context of a turbine blade, it will be recognized that the invention is not so limited.
Conventionally, the life of high speed components, such as a turbine blade employed in aircraft engine, is enhanced by designing the component to resist or minimize the imposed stresses. This involves designing the turbine blade so that the natural vibrational frequencies do not match the vibrational frequencies produced by the high speeds. A turbine blade designed in this way minimizes the stress amplitude by avoiding a resonant effect that amplifies the stresses. It is not always possible however, to design a blade that has adequately different natural vibrational frequencies from those produced by the high speed motion.
Another turbine blade design approach attempts to dampen the vibrations at critical locations on the blade. Various damping designs, such as friction damping or the application of damping coatings, are available to help reduce the stress amplitude at the critical locations. Damping is often expensive, involves highly complex analysis and experimentation, and may impair the performance of the turbine blade.
Accordingly, a metallic component, such as aircraft engine turbine blade, that provides enhanced high cycle fatigue life is needed.